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Home » MSG in vaccines are not dangerous – debunking more anti-vax nonsense

MSG in vaccines are not dangerous – debunking more anti-vax nonsense

There are so many random claims from the anti-vaccine activists about evil chemicals in your child’s vaccines – now, MSG in vaccines. Of course, MSG isn’t the only evil chemical that causes anti-vaxxers to scream loudly.

Aluminum in vaccines is dangerous? Actually, no. Mercury in vaccines? No again. Formaldehyde in vaccines is killing our kids? Nope. Of course, MSG in vaccines is causing something. Anything.

Of course, many of you have heard about MSG in our food. It’s up there on the evil food chemical list along with aspartame, high fructose corn syrup, GMO‘s, and whatever else is the food danger of the day. But MSG certainly has been on the top of the “avoid” list for decades.

I’ve been refuting nonsense about chemicals for at least 25 years on the internet (back before we had social media, yeah I’m an old dinosaur). From my perspective, I think that 50% of the issues with “chemicals” are their long complex names. And the other 50% is because of the appeal to nature logical fallacy, which is the argument that natural substances are somehow superior to “chemicals.” 

Ironically, everything in nature is a chemical, and unless you think everything in the universe is designed for human health (ridiculous), a “natural” chemical is not even close to being superior to a “man-made” chemical. 

But let’s get back to MSG – how many times have you seen “No MSG” in a sign Chinese restaurant? So if we don’t want to put MSG in our kung pao chicken, then why would we want MSG in vaccines? 

What we’re going to show in this article is that MSG dangers are a myth. And the dangers of MSG in vaccines are a bigger myth. 

MSG in vaccines
3D MSG molecule

What is MSG? Science part 1

MSG, or monosodium glutamate, is simply the sodium salt, or the ionic form, of glutamic acid, an amino acid that is one of the building blocks of most proteins. All proteins, in all living organisms, are a chain of amino acids, one of which could be glutamic acid. 

You consume glutamic acid from almost every food you eat from grains to meat since it’s a constituent part of probably every protein found on the planet. Some grain proteins have over 30% by weight glutamic acid. Since glutamic acid doesn’t exist except in the presence of water, it precipitates out of solution in the presence of sodium or other cations (potassium, lithium, and others).

Hence, the “monosodium” part of MSG. It is the salt form of glutamic acid. Of course, someone will claim that somehow the salt form is different than the acid form. That’s not chemistry that most of us scientists learned back in the day.

Precipitated salts do not change their essential chemical nature, because a glutamate ion does not exist without water unless it combines with a cation. So, the MSG you find in the powdered form will immediately split into a sodium ion and glutamate ion – and the body can use that glutamate for any biochemical process it wants, and excess sodium is excreted through the kidneys.

Let me repeat that. MSG just dissolves into one sodium ion and one glutamate ion once you consume it. And that glutamate ion passes from your gastrointestinal tract into your blood, then it is taken up by cells to be used to build all kinds of proteins necessary for running that cell. 

Here’s the actual science behind glutamates (you can ignore this paragraph if chemistry makes your eyes glaze over). When glutamic acid or one of its salts is dissolved in aqueous solutions, a pH-dependent instantaneous chemical equilibrium of the amino acid’s ionized forms, including zwitterionic forms, will result.

These forms are called glutamates. Salts exist only in a dry and crystallized form. The form ultimately responsible for the taste is the glutamate ion, and the form of glutamic acid at the time of the addition is not important. However, crystalline glutamic acid salts such as monosodium glutamate dissolve much better and faster than crystalline glutamic acid, a property important for use as a flavor enhancer.

Glutamic acid, one of the amino acids upon which nearly every single protein is built in the human body, is chemically indistinguishable from the acid salt, MSG. Once you ingest MSG, it dissociates into sodium and glutamate, which will be absorbed and utilized by the body. Moreover, all glutamates are the same – if they are manufactured by a human cell, a plant, some algae, or a chemistry laboratory, they are chemically identical.

Glutamic acid does not suddenly change properties when in salt form. Once it’s consumed, the glutamate separates from the sodium and binds with hydrogen to become an acid again. The sodium is either utilized by the body or excreted through the kidneys.  It’s a simple physiological process, no mystery at all.

I know this sounds like I’m repeating myself, but I’m trying to make it clear that MSG, glutamate, and glutamic acid are biochemically equivalent.

All forms of glutamate/glutamic acid/MSG are exactly the same from a chemical standpoint. The human body cannot tell the difference between the amino acid, glutamic acid/ the salt form of that acid, monosodium glutamate; or the ionic form, glutamate. You might want to invent some difference between the three forms, to make some case that MSG is more dangerous, but that would require a complete rewriting of what we know about basic chemistry. And you’d win a Nobel Prize for doing so.

MSG myth
There are three chemical forms of glutamate. They all become the bottom form, which is what the human body “sees.”

What is MSG? Science part 2

Yes, I need to go into even more science, so that we are perfectly clear about glutamates (MSG or glutamic acid).

Let me repeat myself (just because this is one of the points of contention) – once you ingest MSG into the liquid environment of the stomach, and it simply dissociates back into one sodium ion and one glutamate ion, and the glutamate is absorbed into the blood to create new proteins. And that glutamate ion is exactly the same as the glutamate ion that will be broken down from every single protein consumed. It’s very simple chemistry, about the simplest I could describe in human physiology.

But there’s more to glutamate than just MSG and proteins that you may consume.

The body produces glutamate (or glutamic acid more properly) during various cellular processes, including the citric acid cycle, or Kreb’s cycle, which is a complex metabolic system fundamental to how the cell builds proteins and provides energy. So, if you avoid MSG/glutamate in your food (which is pretty much impossible), don’t worry, your body will produce all the glutamate it needs to survive. Because we definitely need glutamate to survive.

Glutamate is also a key compound in eliminating and controlling the waste nitrogen in the body (which is created by cells in the form of urea). It is also a neurotransmitter, used by nerve cells to transmit certain types of information, and is a critical substance in cognitive functions in memory and learning. In other words, glutamate is very important in your life.  Without it, you will probably die. Or at least not be able to think.

So if you eat a lot of glutamate in your food, and your body synthesizes glutamate in substantial quantities, is there anything bad about MSG?

Well, there may be an issue that might arise. MSG does have a sodium ion, but it’s actually less by weight than an equivalent amount of table salt. Interestingly, in a 1984 Journal of Food Science article, MSG may actually be useful in reducing sodium consumption while not compromising taste in savory foods. Salt is considered a fundamental additive to good tasting savory foods, and MSG could make an improved taste, with less sodium.

In fact, I’ve always contended that many of the symptoms observed after eating Chinese food have more to do with sodium since a lot of components of Chinese food include soy sauce, a high salt ingredient. MSG does contribute sodium to the equation, so it might actually add to the sodium burden of the food.

High salt consumption has a lot of effects that mirror the complaints about MSG itself. But after a few hours, a well-functioning kidney will clear out the extra sodium (as long as you drink a lot of water). And usually, within those few hours, you are back to normal sodium, and all that glutamate you consumed has been incorporated into billions of proteins in your body.

Is there some level of glutamate (glutamic acid or MSG) which could cause harm? Like I mentioned above, the salt form, MSG, has one sodium ion, so it could cause harm if you consumed a lot. But that could happen with table salt.

Furthermore, biochemical and physiological processes are quite robust in managing excess amino acids, like glutamic acid. Let’s say you eat some protein source that’s high in glutamate (and you throw in a few dashes of MSG just because), it’s difficult to imagine sufficient glutamate that would cause harm. Several biochemical processes might convert excess glutamate into other amino acids or into various enzymes and proteins in the cell. 

In a nutshell, there is not a lot of peer-reviewed evidence that MSG does anything to the body. In fact, as we shall see, there’s a ton of repeated, robust, published evidence that suggests that there is no causal link between MSG and any deleterious health condition. 

Chinese food with MSG. Very safe. Photo by Drew Taylor on Unsplash.

Why do we use MSG in food?

MSG has no taste by itself, but it is used by many professional chefs as a flavor enhancer, improving and enhancing the flavor of almost any food. The taste that is enhanced by MSG is different than the standard sour, sweet, bitter, and salty flavors – it is called “umami,” which also is enhanced by substances like soy sauce. It’s the savory flavor that one finds that is different from the commonly stated “four tastes” that chefs used to consider when developing flavors for food.

The taste-enhancing quality of MSG is not well understood, but it’s possible that humans evolved the pleasurable taste of umami as a result of natural selection favoring those who had a pleasurable reaction to eating high-quality protein foods – that is, the food that provides more nutrients (proteins) tastes better. And that would include glutamate.

MSG has been used as a flavor enhancer for several thousand years. It is one of the key components of many Asian cuisines, especially in the Japanese and Chinese cultures, who have extracted MSG from kelp for centuries. The Romans used a sauce called garummade from fermented fish, that was used instead of more expensive salt. Garum is rich in monosodium glutamate, so the use of MSG isn’t a product of modern chemistry, but has been around for thousands of years.

MSG was discovered and identified in 1866 by a German chemist who treated wheat gluten (oh geez, I see the conspiracies forming about evil gluten) with sulfuric acid. In 1908, a Japanese scientist, Kikunae Ikea,  isolated glutamic acid as a taste substance back in 1908 from the seaweed. He called its taste umami.

In other words, from a scientific and pragmatic point of view, MSG is a natural substance from naturally grown plants. MSG wasn’t invented by Monsanto and forced down the throat of innocent people everywhere. It’s been a flavor enhancer for a few millennia.

Restaurant in Japan. Lots of MSG not hurting anyone. Photo by Lan Pham on Unsplash

What started the MSG phobia?

The MSG phobia probably started with personal anecdotes after eating Chinese food. In 1968, a physician complained about radiating pain in his arms, weakness, and heart palpitations after eating at Chinese restaurants. He wrote about his personal experience in a letter to the New England Journal of Medicine.

However, the physician hypothesized that either cooking wine, MSG or excessive salt might be problematic. Other letters were published stating similar experiences after consuming Chinese food.

A 1969 article in Science claimed there was a dose-response relationship between Chinese food and the Chinese Restaurant Syndrome (CRS).  But the study did not isolate MSG as the cause and was not blinded (which would be nearly impossible if were to determine if the cause was the food rather than the ingredients).  Unfortunately, the study has never been repeated, so it’s impossible to determine if it provides evidence that Chinese food does anything, let alone MSG.

According to Anna Maria Barry-Jester, writing in FiveThirtyEight, there were some issues:

Early on, researchers reported an association between consuming MSG and the symptoms cited in the New England Journal of Medicine. Inflammatory headlines and book titles followed: “Chinese food make you crazy? MSG is No. 1 Suspect,” wrote the Chicago Tribune, while books titled “Excitotoxins: The Taste That Kills” and “In Bad Taste: The MSG Symptom Complex” prompted FDA reviews and “60 Minutes” investigations, as Alan Levinovitz, a professor of Chinese philosophy at James Madison University, chronicled in a 2015 book about food myths.

But those early studies had essential flaws, including that participants knew whether or not they were consuming MSG. Subsequent research has found that the vast majority of people, even those claiming a sensitivity to MSG, don’t have any reaction when they don’t know they are eating it.

That MSG causes health problems may have thrived on racially charged biases and xenophobia right from the outset. Ian Mosby, a food historian, wrote in a 2009 paper titled “‘That Won-Ton Soup Headache’: The Chinese Restaurant Syndrome, MSG and the Making of American Food, 1968-1980” that fear of MSG in Chinese food is part of the U.S.’s long history of viewing the “exotic” cuisine of Asia as dangerous or dirty.

As Mosby put it: “It was the misfortune of Chinese cooks to be caught with the white powder by their stoves when the once-praised flavor enhancer suddenly became a chemical additive.”

And of course, the usual suspects in pushing food and medical ignorance love to pontificate on MSG, even today. Joe Mercola, one of the leading purveyors of nonsense science and medicine, calls MSG “the silent killer lurking in your kitchen cabinets.” Oh, my.

His claims are based on a belief that MSG is an excitotoxin, which causes a pathological process by which nerve cells are damaged and killed by excessive stimulation by neurotransmitters. This pseudoscience is promoted by  Dr. Russell Blaylock, a board-certified neurosurgeon and author of “Excitotoxins: The Taste that Kills.” Setting aside the appeal to false authority (a board-certified neurosurgeon may not have any actual knowledge of neurochemistry), a book isn’t necessarily a high-quality source.

Despite these claims, there is little independent, robust, and unbiased evidence that MSG does anything to nerve cells. In fact, you consume so much glutamate in normal food, if there were things like MSG and neurological issues, it would be so prevalent that the human species would have died out long ago.

I have not found any compelling scientific evidence that supports even a rare incidence of MSG sensitivity.

Best scientific evidence about MSG

But is there any evidence that MSG is dangerous to humans?  In a word, no. Here are some of the many meta-reviews and high-quality clinical trials that debunk the MSG myth –

These review articles, which are meta-analyses of a large number of primary research articles, along with clinical trials, just don’t support the MSG myth. There might be a small subpopulation of people who are sensitive to MSG, but even that has little support in the scientific evidence and is completely dismissed in systematic reviews.

Sashimi and soy sauce. The Skeptical Raptor approves. Photo by Luigi Pozzoli on Unsplash

Finally, MSG in vaccines

Yes, I spent a few thousand words about MSG without getting to vaccines, because it is important to lay out the case that MSG is not dangerous, except in the minds of pseudoscientists. And because there are some delicious food photos added.

So, let’s talk about MSG in vaccines.

MSG is used in a few vaccines. According to the CDC, it is used as stabilizers in a few vaccines to help the vaccine remain unchanged when the vaccine is exposed to heat, light, acidity, or humidity. 

I occasionally joke that people think that making vaccines is easy – throw some water, a bunch of evil chemicals, fetuses, mice, cancer cells, and the virus (or bacteria) in a blender, pour it into vials, and voilà, we have a vaccine. 

Setting aside my sarcasm, vaccines are kind of delicate. Once the scientists get all the ingredients just right to induce an immune response safely, they have to make sure the vaccine is effective even after several months before use. MSG in vaccines is used to stabilize or buffer the solution so that the antigens, necessary to invoke an immune response, do not break down over time. 

MSG is actually only used in four vaccinesadenovirus (only given to new recruits in the US military), chickenpox, shingles, and FluMist vaccines. However, you all know how the anti-vaccine zealots push their narrative – if it’s in one vaccine, it’s in every vaccine. But it’s really only four vaccines, one that’s used in a very specific population.

Let’s look at how much MSG is in some of these vaccines:

  • FluMist has 188 µg (1 µg, or microgram, is equal to one-millionth of a gram) MSG per dose.
  • The chickenpox vaccine, Zostavax, has 620 µg MSG per dose.
  • The shingles vaccine, Varivax, has 500 µg MSG per dose.

The website Harpocrates Speaks put these amounts into the context of the amount of MSG we consume in regular foods:

  • 1/2 cup of peas contains 48 times the glutamate in Varivax and 127 times the amount in FluMist.
  • One cup of breast milk contains 352 times the amount found in Varivax and 936 times the amount in FluMist.
  • The safe, daily intake of glutamate is 12,000 times the MSG in Varivax and 32,000 times what is in FluMist.
MSG in vaccines

Just in case you were wondering, here are some glutamate levels in some foods that you might eat every day, let me repeat what you see in the chart above:

  • Human breast milk, 22,000 µg glutamate per 100 g (or about 3.5 ounces in the barbarian American system, see Note 1)
  • Ham, 337,000 µg/100 g
  • Tomato juice, 260,000 µg/100 g
  • Parmesan cheese, 1,680,000 µg/100 g
  • Soy sauce, 1,264,000 µg/100 g
  • Corn, 106,000 µg/100 g

In other words, MSG in vaccines is equivalent to a tiny speck compared to what we consume every single moment of every single day. And if you’re going with the argument that “injected” MSG is somehow different than “ingested” MSG, it’s a bogus claim. MSG = glutamate, no matter how it gets in the body.

Obligatory cute pet photo. Photo by Shoeib Abolhassani on Unsplash

The TL;DR version of MSG in vaccines

MSG is just a simple salt of glutamic acid, one of the 20 or so amino acids that are the building blocks of every protein in humans (and every other organism on Earth). The glutamate in MSG is chemically and biologically indistinguishable, even at the atomic level, from all other glutamates on the planet.

Let me repeat this once again. All glutamates are the same. The glutamate in seaweed or manufactured from some process in a lab are equivalent to the ones produced by humans.

Unless you consume a massive amount of the substance, which is nearly impossible, MSG is safe for almost all humans.  Go have a spoonful. Or put it on your food, because it does make it tastier. But it isn’t going to hurt you unless for some illogical reason you think it will.

And because MSG is safe, any MSG in vaccines (and that’s just four of them) is also safe. But more than that, the amount of MSG in vaccines is overshadowed by the hundreds of thousands of times more glutamate found in all foods. 

Does this end the myth about MSG in vaccines or foods? No, but we keep trying!


  1. Unfortunately, this data is from the US FDA, and the measurements are in barbarian imperial US customary units, an anachronistic, ridiculous, illogical, and useless system of measurements. Even though this feathered dinosaur is a US citizen, he only uses the wonderful, logical, modern metric system. 

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